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Ten top tips on antibiotic prescribing

Consultant medical microbiologist Dr Cliodna McNulty offers key pointers on rationalising antibiotic prescribing

1. Delayed prescribing can reduce antibiotic use and increase self-care.

NICE guidance suggests a no-prescribing or delayed-prescribing strategy for most acute uncomplicated respiratory tract infections.1 This is a particularly useful approach in patients who have had antibiotics in the last two years, who are twice as likely to reconsult with future respiratory tract infections – a delayed prescription in this group reduces antibiotic use by 78%. Give the patient advice on using the antibiotic if their symptoms get significantly worse, or if they do not settle in accordance with the expected duration for that illness.

2.  The Centor criteria are very useful to target antibiotic use in acute sore throats.

The Centor criteria are: history of fever, absence of cough, tender anterior cervical lymphadenopathy and tonsillar exudates. Patients with a low Centor score (0-2) are much less likely to respond to antibiotics than high scorers as they have a low chance of having Group A ß-haemolytic streptococcal infection (negative predictive value 80%). Those with a Centor score of three or four have a much higher chance of this type of infection, and can be offered a delayed or immediate course of antibiotics, depending on illness severity and patient choice.

3. In acute otitis externa, topical acetic acid has similar cure rates to topical antibiotics.

A Cochrane meta-analysis shows that topical treatments are adequate for treating most cases of acute otitis externa and acetic acid was as effective as antibiotic or steroid.2 But it is important to advise patients to use drops for at least a week, and to continue for up to 14 days if symptoms persist.

4. It is important to optimise analgesia and target antibiotics in children with acute otitis media.

We know that parents actually tend to underestimate the amount of analgesia their children need and, as 66% of acute otitis media cases resolve within 24 hours without antibiotics, it is important adequate analgesia is given. But consider antibiotics in those at risk of prolonged illness, all children with otorrhoea or children under two years with bilateral acute otitis media or marked otoscopic signs and four or more of the following: fever, tugging ears, crying more, irritability, difficulty sleeping, less playful or eating less.

5.  Patients with cellulitis can be treated with flucloxacillin alone.

Flucloxacillin has activity against both Group A ß-haemolytic streptococcus, which is the most common cause of cellulitis, and Staphylococcus aureus. There is no need to use co-amoxiclav except in facial cellulitis, or in cellulitis following bites when other organisms including anaerobes may be involved.

6. Leg ulcers are commonly colonised – only send swabs when there are clinical signs of infection.

Leg ulcer swabs will only tell you what organisms are present – the diagnosis of significant infection is a clinical one. Do not treat just because you have been given a positive culture result or an assessment of antibiotic sensitivity by the lab – they do not know the full clinical details. Consider infection if there is increasing pain, an enlarging ulcer, cellulitis and pyrexia.

7 . Consider antibiotic choice and duration in urinary tract infection.

Do not assume that every patient with a positive urine result needs antibiotics. Many antibiotics are prescribed following a urine culture result sent by another clinician, so always check for symptoms. Treatment of asymptomatic bacteriuria in the elderly or those with catheters does not reduce morbidity, but will increase the risk of resistance and increase the risk of thrush and Clostridium difficile diarrhoea. In the elderly, two or more signs of urine infection – especially dysuria, fever higher than 38°C or new incontinence – should prompt treatment.

Three days' treatment is as effective as five or seven days in all women with acute uncomplicated UTI. Despite rising resistance, trimethoprim is still the first-line treatment in most women. In areas with higher resistance or in women with recurrence, nitrofurantoin is still active against most organisms, including the more resistant ß-lactamases. If there are few symptoms, or symptoms are mild, use a dipstick to guide treatment. But prescribe empirical antibiotics if symptoms are severe or there are three or more symptoms.

8.  Uncomplicated conjunctivitis does not need antibiotics.

Several community studies have found no significant difference between placebo and chloramphenicol or fusidic acid. So only treat if the conjunctivitis is severe and likely to be bacterial – usually this is unilateral red eye with mucopurulent, not watery, discharge. Do treat if you suspect ophthalmic shingles.

9. Do not use antibiotics in eczema unless infected.

Topical or oral antibiotics with or without steroids do not hasten improvement of eczema unless overt signs of infection are present. Topical fusidic acid should only be used for very localised lesions of infection, as widespread use may increase resistance and reduce the value of the oral formulation. Mupirocin should be reserved for MRSA.

10. Get all prescribers in your practice to agree on a policy for common infections.

Consistency in approach will discourage patients from making an additional appointment with another GP when they have not been prescribed an antibiotic for a self-limiting infection. Use local guidance from your PCT or for more information visit the Health Protection Agency website at

Dr Cliodna McNulty is a consultant medical microbiologist at Gloucestershire Royal Hospital and head of the Health Protection Agency's primary care unit.

The advice in this article is based on evidence-based management of infection guides and diagnostic guides by the Health Protection Agency, now used by most PCTs and health boards across the UK to produce their local antibiotic guidance. The guidance is available on the HPA website ( or at


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